Saved in:
Bibliographic Details
Main Authors: Zhan, Qishi, Hu, Minxuan, Wang, Guansu, Liu, Jiaxin, He, Liang
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2604.23102
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866918467637084160
author Zhan, Qishi
Hu, Minxuan
Wang, Guansu
Liu, Jiaxin
He, Liang
author_facet Zhan, Qishi
Hu, Minxuan
Wang, Guansu
Liu, Jiaxin
He, Liang
contents Standard evaluations of Bayesian deep learning methods assume that metric estimates are reliable, but we show this assumption fails under data scarcity. Method rankings are not only unreliable at small $n$, but also dataset-dependent in ways that point estimates cannot reveal: the same method comparison yields $P(\mathrm{MCD} \prec \mathrm{Ensemble}) = 1.000$ at $n = 50$ on one dataset and remains below $0.95$ even at $n = 500$ on another. Across the datasets we consider, no universal sample size threshold exists, which is precisely why dataset-specific posterior inference is necessary. To address this, we use a Bayesian hierarchical model with method-specific variances to treat evaluation metrics as random variables across data realizations, and we use a predictive Minimum Detectable Difference curve to assess whether an observed gap would be detectable at a given training size. Across six Bayesian deep learning methods and five regression datasets, our results show that uncertainty-aware evaluation is necessary in low-data settings, because current evidence for method superiority and predictive detectability at the same training size can diverge substantially. Our framework provides practitioners with principled tools to determine whether their evaluation data is sufficient before drawing conclusions about method superiority.
format Preprint
id arxiv_https___arxiv_org_abs_2604_23102
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Unstable Rankings in Bayesian Deep Learning Evaluation
Zhan, Qishi
Hu, Minxuan
Wang, Guansu
Liu, Jiaxin
He, Liang
Machine Learning
Standard evaluations of Bayesian deep learning methods assume that metric estimates are reliable, but we show this assumption fails under data scarcity. Method rankings are not only unreliable at small $n$, but also dataset-dependent in ways that point estimates cannot reveal: the same method comparison yields $P(\mathrm{MCD} \prec \mathrm{Ensemble}) = 1.000$ at $n = 50$ on one dataset and remains below $0.95$ even at $n = 500$ on another. Across the datasets we consider, no universal sample size threshold exists, which is precisely why dataset-specific posterior inference is necessary. To address this, we use a Bayesian hierarchical model with method-specific variances to treat evaluation metrics as random variables across data realizations, and we use a predictive Minimum Detectable Difference curve to assess whether an observed gap would be detectable at a given training size. Across six Bayesian deep learning methods and five regression datasets, our results show that uncertainty-aware evaluation is necessary in low-data settings, because current evidence for method superiority and predictive detectability at the same training size can diverge substantially. Our framework provides practitioners with principled tools to determine whether their evaluation data is sufficient before drawing conclusions about method superiority.
title Unstable Rankings in Bayesian Deep Learning Evaluation
topic Machine Learning
url https://arxiv.org/abs/2604.23102